Clarify the setup enviornment instructions
Clarify the setup enviornment instructions

* the GitHub organization name is known
* change the wording on what the `cd` command does
* use the same path in both examples

Signed-off-by: Nathen Harvey <nharvey@chef.io>

Pull request: #549
Approved by: metadave

rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,nathenharvey/habitat,georgemarshall/habitat,rsertelon/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,nathenharvey/habitat,nathenharvey/habitat,nathenharvey/habitat,georgemarshall/habitat,rsertelon/habitat,georgemarshall/habitat,habitat-sh/habitat,habitat-sh/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,nathenharvey/habitat,rsertelon/habitat,georgemarshall/habitat